Topic 2 - States Of Matter & Seperating/purifying Substances Flashcards
(43 cards)
A substance is heated at a constant rate and its temperature is taken every minute.
During the heating, the substance undergoes one change of state.
The results are shown on the graph in Figure 5.
Explain the shape of the graph in terms of the changes in the movement and arrangement of
the particles as the substance is heated. (4)
Positive gradient AB - horizontal line BC - positive gradient CD
From B to C, graph is flat because particles in solid use energy to break out of lattice/particles become randomly arranged/turn from solid to liquid (1)
From A to B, graph rises because particles in solid are in a lattice (1) so vibrate more rapidly as temperature increases (1)
From C to D, graph rises because particles in liquid move past one another/randomly (1) particles move more rapidly as temperature increases (1)
An ink is a mixture of coloured substances dissolved in water.
Changes of state between the 3 states of matter are shown below.
Explain why these changes are called physical changes rather than chemical changes. (2)
(Melting) (evaporating)
Solid → liquid → gas
Gas → liquid → solid
(Condensing) (freezing)
Physical changes do not result in the formation of a new substance (1)
Physical changes can be easily reversed (1)
Describe the differences in the arrangement and movement of the particles in a solid and in
a liquid. (2)
In a solid, particles are regularly arranged/ in a liquid, they are randomly arranged (1)
In a solid, particles don’t move around (only vibrate)/in a liquid, particles move around (1)
Here are five statements about ice and water.
Place ticks in boxes by the two statements that are correct. (2)
The molecules move faster in water than in ice
The molecules are more randomly arranged in ice than in water
The molecules start moving when wage becomes ice
The molecules are arranged regularly in ice but not in water
The molecules have more energy in ice than in water
The molecules move faster in water than in ice (1)
The molecules are arranged regularly in ice but not in water (1)
Overhead power lines are made of aluminium with a steel core.
Figure 5 shows some properties of steel and aluminium.
Explain why the power lines are made of aluminium with a steel core rather than pure
aluminium. (2)
Steel = high strength 7.87 density
Aluminium = low strength 2.70 density
Aluminium has low strength/steel has high strength (1)
Steel is added to make the power line stronger (1)
Which of the following substances will be a solid at 20 °C and will melt when placed in a
beaker of hot water at 80 °C? (1)
MP = 122 BP = 249
MP = -7 BP = 59
MP = 30 BP = 2403
MP = -32 BP = 27
MP = 30 BP = 2403
The 3 states of matter are solid, liquid and gas.
Figure 2 shows the melting points and boiling points of four substances, W, X, Y and Z.
Using the information below:
give the letter of the substance that is a solid at 20 °C (1) …………………………
give the letter of a substance that is a liquid at 50 °C (1) ……………………….
W MP= -220 BP= -188
X MP= -101 BP= -34
Y MP= -7 BP=59
Z MP= 114 BP=184
Z (1)
Y (1)
Potable water is water that is suitable for drinking.
River water can be treated to make it potable.
Chlorination, filtration and sedimentation are 3 of the processes involved in making the river water potable.
Which row shows these 3 processes in the order in which they are carried out? (1)
Chlorination Sedimentation Filtration
Chlorination Filtration Sedimentation
Sedimentation Filtration Chlorination
Sedimentation Chlorination Filtration
Sedimentation Filtration Chlorination
State the reason why chlorine is added during water treatment. (1)
To kill bacteria/microorganisms
Describe how sedimentation is carried out. (2)
Waste water is left in a tank to settle (1)
Sediment/particles/dirt falls to the bottom (1)
Figure 5 shows the results of an analysis of a sample of potable water.
Explain why this sample of potable water is not the same as pure water. (2)
Chloride concentration = 60.70
Fluoride concentration = 0.24
Nitrate concentration = 24.90
Sulfate concentration = 71.40
Copper concentration = 0.05
Magnesium concentration = 9.10
The water contains ions/salts/any from above (1)
Pure water doesn’t contain ions/more than just water molecules/which are impurities (1)
Samples of four inks, W, X, Y and Z, were separated using paper chromatography.
State what could be changed in the experiment to make the Rf value more accurate. (1)
Longer paper/different paper/medium
In a chromatography experiment, ink sample Y did not move from the start line.
Explain a change to the experiment that would be needed to separate the dyes in ink sample Y. (2)
Use a different solvent (1)
So that the ink will dissolve (1)
Use words from the box to complete the sentences. (3)
Simple distillation is used to separate a liquid from a …………………………………………………..
Vapour is cooled to form liquid. This process is called …………………………………………………..
The liquid collected in the beaker is known as the …………………………………………………..
Solid (1)
Condensation (1)
Distillate (1)
Pure water collects in the beaker.
Explain how the apparatus will show that the liquid collected is pure water.
A thermometer (1)
Should show the boiling point of water (1)
Waste water can be used to produce drinking water.
The processes used include sedimentation, filtration and chlorination.
What is sedimentation? (1)
the waste water is heated so the impurities evaporate
the waste water has an acid added to remove impurities
the impurities in the waste water settle to the bottom of their container
the impurities in the waste water are bleached
the impurities in the waste water settle to the bottom of their container
State why waste water is filtered in water treatment. (1)
To remove solids/insoluble substances
Describe how a sample of pure, dry sodium chloride crystals can be obtained from the
filtrate. (3)
Heat solution (to concentrate it) (1)
Leave solution in warm place to crystallise (1)
Scrape crystals from container/pat dry between filter papers (1)
In a different method of obtaining nickel, the process produces a mixture of the liquids nickel
tetracarbonyl and iron pentacarbonyl.
The BP of nickel tetracarbonyl is 43°C.
The BP of iron pentacarbonyl is 103°C.
These two liquids mix together completely.
Describe the process used to separate these liquids. (3)
Fractional distillation (1)
Heat/boil (1)
nickel tetracarbonyl boils off first/is obtained from the top of the fractionating column (1)
A sample of water was contaminated with a dissolved solid.
Devise a plan to separate pure water from this mixture, including a test to show that the water obtained is neutral. (6)
SEPARATION
• distillation
• solution in flask
• heat
• water evaporates
• water vapour into condenser
• cooling water jacket
• water vapour condensed back to liquid
• water collected in beaker
• solid remains in flask
• boiling point = 100°C
TEST
• take distilled water in a test tube
• add a few drops of neutral litmus/Universal Indicator
• correct neutral colour OR
• pH probe
• pH = 7
A student set up the apparatus shown below to obtain pure water from sea water by distillation.
Explain how the water in sea water separates to produce the pure water in this
apparatus. (2) ………………….
Explain how the apparatus could be improved to increase the amount of pure water
collected from the same volume of sea water. (2) …………………..
Heat, conical flask, straw, delivery tube, seawater
Water boils/evaporates to form steam (1) steam condenses to form pure water (1)
Use a Liebig condenser/wrap delivery tube with cold cloth (1) to increase effectiveness of cooling/amount of condensation (1)
In analysis, tests are carried out on solids dissolved in water.
Explain why it is important that the water used is pure. (2)
Pure water has no other ions present (1)
Ions may give a false/incorrect result (1)
Explain how filter paper separates an insoluble solid from a liquid. (2)
Liquids pass through the paper (1)
Solids do not (1)
Paper chromatography was used to try to separate the coloured substances in five food
colourings, V, W, X, Y and Z.
The paper was placed in a beaker with the bottom of the paper in the solvent.
Identify the stationary phase in this experiment. (1) …….…………
Give a reason why the spots of the food colourings must be above the level of the
solvent, when the paper is placed in the solvent. (1) ……………..
Water (1)
Otherwise the spots transfer into the solvent (1)
